The interaction between Pseudomonas aeruginosa cells and cationic PC:Chol:DOTAP liposomal vesicles versus outer-membrane structure and envelope properties of bacterial cell.
The interactions between cationic liposomal formulations (PC:Chol:DOTAP 3:4:3) and 23 Pseudomonas aeruginosa strains were tested. The study was undertaken because different antimicrobial results had been obtained by the authors for Pseudomonas aeruginosa strains and liposomal antibiotics (Drulis-Kawa, Z., Gubernator, J., Dorotkiewicz-Jach, A., Doroszkiewicz, W., Kozubek, A., 2006. The comparison of in vitro antimicrobial activity of liposomes containing meropenem and gentamicin. Cell. Mol. Biol. Lett., 11, 360-375; Drulis-Kawa, Z., Gubernator, J., Dorotkiewicz-Jach, A., Doroszkiewicz W., Kozubek, A., 2006. In vitro antimicrobial activity of liposomal meropenem against Pseudomonas aeruginosa strains. Int. J. Pharm., 315, 59-66). The experiments evaluate the roles of the bacterial outer-membrane structure, especially outer-membrane proteins and LPS, and envelope properties (hydrophobicity and electrostatic potential) in the interactions/fusion process between cells and lipid vesicles. The interactions were examined by fluorescent microscopy using PE-rhodamine-labelled liposomes. Some of the strains exhibited red-light emission (fusion with vesicles or vesicles surrounding the cell) and some showed negative reaction (no red-light emission). The main aim of the study was to determine what kinds of bacterial structure or envelope properties have a major influence on the fusion process. Negatively charged cells and hydrophobic properties promote interaction with cationic lipid vesicles, but no specific correlation was noted for the tested strains. A similar situation concerned LPS structure, where parent strains and their mutants possessing identical ladder-like band patterns in SDS-PAGE analysis exhibited totally different results with fluorescent microscopy. Outer-membrane protein analysis showed that an 18-kDA protein occurred in the isolates showing fusion with rhodamine-labelled vesicles and, conversely, strains lacking the 18-kDA protein exhibited no positive reaction (red emission). This suggests that even one protein may be responsible for favouring stronger interactions between Pseudomonas aeruginosa cells and cationic liposomal formulations (PC:Chol:DOTAP 3:4:3).
Drulis-Kawa
Zuzanna
Z
Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland. kawa@microb.uni.wroc.pl
Dorotkiewicz-Jach
Agata
A
Gubernator
Jerzy
J
Gula
Grzegorz
G
Bocer
Tomasz
T
Doroszkiewicz
Wlodzimierz
W
D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D002412:Cations; D002473:Cell Wall / Q000187:drug effects* / Q000378:metabolism; D002784:Cholesterol / Q000737:chemistry / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry / Q000494:pharmacology*; D005456:Fluorescent Dyes; D057927:Hydrophobic and Hydrophilic Interactions; D008070:Lipopolysaccharides / Q000378:metabolism; D008081:Liposomes; D008856:Microscopy, Fluorescence; D010713:Phosphatidylcholines / Q000737:chemistry / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000494:pharmacology*; D055672:Static Electricity
D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D002412:Cations; D005229:Fatty Acids, Monounsaturated; D005456:Fluorescent Dyes; D008070:Lipopolysaccharides; D008081:Liposomes; D010713:Phosphatidylcholines; D000644:Quaternary Ammonium Compounds; D002784:Cholesterol; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane